If you have a good AAA rep, not having control of your reservation shouldn't be too big of a deal. They can make adjustments to your reservation for you, but you can't call disney and do it yourself. They can change the package discount you are getting at any time (depending on your AAA rep's hours).
Savings on your room or room portion of your reservation ranges 10-25%.
AAA has their own version of many of Disney's package deals - Meaning it is the exact same package as if you call Disney, however the code(?) is different. These packages have several of the little perks. Storytime, special parking (all parking is free, but AAA has their own section in the lot. It isn't necessarily the closest, but is often pretty good and pretty close. This is especially good when it is crowded. There is the discount card for shopping and I think tours(?). They also are starting special viewing area for the fireworks and parades I think.
There are other packages though that AAA does not have their own version of, or otherwise do not include all of the perks. I know parking is still included but I don't know what else. I know that the last two times I went, we did not get the story time because of the package we were booking. I do not know how much things may have changed for this year, but the wording remains "When you purchase select AAA Vacations® packages that include a dining plan" (referencing storytime), I think I saw the same wording for the special viewing events as well.